A known sealing device for a connector is shown in FIG. 15. It prevents entrance of water into cavity 97 which accommodates terminal fitting 96. This structure employs a cylindrical sealing member 90 of rubber. First, wire 95 is inserted into center hole 91 of member 90. Terminal fitting 96 is then cramped around wire 95, and sealing member 90 is moved to a position adjacent terminal fitting 96. Member 90 is pressed into cavity 97 at the same time terminal fitting 96 is inserted.
When fitted in cavity 97, sealing member 90 is radially compressed, resulting in deformation of projections 92 which are formed on the outer surface of sealing member 90 and extend circumferentially thereof. Deformed projections 92 come into sealing contact with the inner surface of cavity 97. Projection 93, which is circumferentially located on the surface of center hole 91, is also deformed, and comes into sealing contact with the outer surface of wire 95. In this way, water is prevented from entering cavity 97, where terminal fitting 96 is mounted, through clearances between the outer surface of sealing member 90 and the inner surface of cavity 97 or between the inner surface of sealing member 90 and the outer surface of wire 95.
However, when a transverse force acts on wire 95 extending out of cavity 97 through center hole 91, sealing member 90 undergoes radical elastic deformation as shown in FIG. 16. As a result, a gap is formed between the inner surface of cavity 97 and projections 92 on the outer surface of sealing member 90. In such a case, water can enter cavity 97 through this gap.
Another known sealing device mountable in a connector is shown in FIG. 17. Connector 101 includes cylindrical terminal fitting cavity 103 which accommodates terminal fitting 102. Fitting 102 comprises insulation barrel 102a for cramping on an insulated part of wire 104 and wire barrel 102b for cramping on the conductive core of wire 104 which is exposed by peeling off its insulation. Member 105 is substantially cylindrical and a plurality of flange-like ribs 105a, having a diameter larger than the inside diameter of cavity 103, are formed on the outer surface thereof. At one end of member 105, there is tube portion 105b, having a smaller diameter than ribs 105a, which can be cramped by insulation barrel 102a.
In use, wire 104 is first inserted into member 105 so that tube portion 105b faces the leading end of wire 104. The insulation on the leading end is peeled off to expose the core, which is then cramped by wire barrel 102b of terminal fitting 102. At the same time, the insulated part of wire 104 and tube portion 105b of the member 105 are cramped by insulation barrel 102a. The thus mounted members are inserted into cavity 103 of connector 101 with terminal fitting 102 leading. When member 105 is inserted, ribs 105a are deformed radially inwardly by the inner wall of cavity 103, since the diameter of ribs 105a is larger than the inside diameter thereof. As a result, member 105 comes into sealing contact with the inner wall of cavity 103, preventing water from entering.
In recent years, high pressure car washing machines have come into common use; they spray water on the vehicle at high pressure, not only on the vehicle body, but also into the engine compartment where the foregoing connector is often used. In such a case, the prior art seal (e.g. member 105) is subjected to water sprayed directly where ribs 105a are in contact with the inner wall of cavity 103. Thus, the high pressure spray may deform ribs 105a axially and thus radially inwardly of cavity 103, and cause a gap between ribs 105a and the inner wall of cavity 103 to form. Such a clearance permits entrance of water which is, of course, undesirable.